Using an EST (expressed sequence tag) approach, we have been able to identify greater than 965 gene clusters from Wuchereria bancrofti microfilariae based on1687 ESTs. Interestingly, a surprisingly high percentage (584/965; 60%) of these clustered ESTs contain a putative signal peptide, and only 6 appear to be GPI anchored. When compared to Brugia malayi (Bm) mf ESTs/Clusters, 45% of the Wb clusters had matches to Bm ESTs (identities ranging from 86-100%) whereas fewer (22%) matched Onchocerca volvulus (Ov) mf ESTs (with identities ranging from 80-100%). [unreadable] [unreadable] Using a phage display L3 cDNA library of Brugia malayi and screens with known human receptors, we have identified, cloned and characterized distinct molecules that bind to the human IL-5R, IL-10R, and IL-13R. The molecule we term, Bm-IL5BP [Brugia malayi IL5 binding protein] has been expressed at high levels in a manner that retains its ability to bind to the human receptor. Antibodies raised to predicted immunogenic peptides inhibit the binding of rBm-IL5BP, and have been used to localize (by immuno-EM) Bm-IL5BP to the surface of the infective stage larvae. The rBm-IL5BP does not itself prolong the survival of human eosinophils, but does inhibit the ability of human IL5 to prolong eosinophil survival. [unreadable] [unreadable] Interestingly, we have also identified a secreted product from Brugia malayi L3 that is chemotactic for human eosinophils. This secreted products signals through the G-coupled receptor CXCR3. [unreadable] [unreadable] Using both first and second generation Brugia malayi expression microarrays, we have been able (not surprisingly) to identify a large number of adult male- and adult female-specific transcripts and corroborate their expression using quantitative RT-PCR. Moreover, we have identified those genes that altered as the infective stage larvae transitions from the mosquito to the human host.[unreadable]